Problem: Luis ate 5 slices of pie. Omar ate 4 slices. If Luis ate $\dfrac{5}{11}$ of the pie, what fraction of the pie was eaten?
Answer: If 5 slices represent $\dfrac{5}{11}$ of the pie, there must have been a total of 11 slices. $\text{fraction of pie eaten} = \dfrac{\text{number of slices eaten}}{\text{number of slices total}}$ They ate ${9}$ out of $11$ slices. They ate $\dfrac{9}{11}$ of the pie.